Sequential and differential valve actuation



` April 7, 1953 E. R. DERRINGTON SEQUENTIAL AND DIFFERENTIAL VALVE ACTUATION Filed April 4, 1947 IIIII.

INVENTOR EDWARD R. DERRINGTON wm N mm mm N mm s vOm m. NN mm Agent Patented Apr. 7, 1953 SEQUENTIAL AND DIFFERENTIAL VALVE ACTUATION Edward R. Derrington, Montrose, Calif., assigner to Lockheed Aircraft Corporation, Burbank,

Calif.

Application April 4, 1947, Serial No. '739,495

3 Claims; (Cl. 137-109) l This invention relates to an improved and simplified means for automatic sequencing and/or differential operation of valves wherein the operationof one fluidcircuit controls the direct or differential operation of another uid circuit. In a more restricted sense the invention relates to the alternative operation of two fluid circuits i with a differential or time delay between the on and off energization ofthe control of one of said circuits.

Thisinvention will be described and explained in connection with the cabin pressurization of gas turbine driven aircraft, yWhether propeller or jet driven. In `such aircraft, of which the P-80 Shooting Starf is `an example, it is permissible to bleed limited quantities of compressed air from the compressor of the gas turbine, for creating a positive pressure in the pilots cockpit or cabin at high elevations', thus avoiding theA need of separate cabin pressurizing equipment. Since air'circuit after a period of shut down;

' In this particular installation the gas turbine compressor may have an intermittent water and/or alcohol mixture injection system to provide a short period of maximum powerfor emergency or take-off purposes. To so Vinject a water and/or alcohol mixture'would load the cabin air bleed with moisture and toxic vapors, causing condensation in the cockpit andk corrosion in the flight instruments also supplied from the cabin air pressure line. Accordingly, it is desirable to automatically shut off the cabin air pressure line before the start'of the injection period, and to restore the cabin air supply at the earliest moment within the acceleration limitations of the air cycle refrigeration turbine.

It is, accordingly, an object of this invention to provide an integrated control of two related services, such as air supply and fluid injection, wherein' thesquencing of the controls of the two services are differentially controlled from a time delay standpoint as between operation in one direction and operation in reverse.

Examples of such i.

systems wherein the coordination of two supply systems can advantageously be diiferentially con--V trolled include fuel and air supplies for internal combustion engines, oil burners, and the like, as well as the water and/or alcohol injection system chosen for illustrative purposes herein.

On the drawing: l 1 Figure 1 is a schematic diagram of a jet turbine equipped with an emergency fluid injection system wherein cabin pressurizing air is with-` draw from the turbine compressor, my invention being applied thereto to shut off the cabin air upon starting the fluid injection and todelay the restoration'of the cabin air supply upon cessation of the fluid injection to the compressor.

Figure 2 is an enlarged fragmentary detail of the arrangement of this invention as applied in Figure 1. i As shown on the drawing, a jet engineer turbine IQ, of a type having a centrifugal compressor and a series of combustion chambers I I, is'shown in elevation since the details thereof are not in# volved herein. A fluid injection system, as used with the turbine, is also shown schematically as a fluid tank l2 from which a pump i3 delivers the fluid to a lter I4 and a diaphragm controlled valve l5 and thence to a manifold 'I6 andindividual injectors l1 discharging into the throats of theV centrifugal compressor impeller (not shown) Because o f the peculiarities of the inlets to the compressor throats and the discharge to the several combustion chambers it `was neces-' sary to use a pair of linjectors corresponding to each combustion chamber, hence the complicated manifold and injection system. A limited quantity or percentage lof "the air compressed by the turbine can be withdrawn therefrom for operation of a cockpit pressurizing system and various pneumatically operated def vices in the airplane, of which the flight instruments are examples.' However, to withdraw `all this air from one point would disturbV the'combust-ion in the combustion chamber receiving its air charge fromadjacent ,suchpoinu according'- ly two or more taps I8 are used to withdraw compressed air from thecompressor discharge scroll and are connected together by a manifold I9 fromwhich lines 29 and 2i supply the cabin air and instruments respectively. v .Since the act of compression heats the air, this compressed air may be directly` usedto heat the,

cabin when conditions so require; and under other conditions it may be necessaryto cool the air before delivery to the cabin. Accordingly, the line 20 is divided and the divided lines are controlled by a mixing and bypass valve 22 which supplies either or both a conduit 23 to an air cycle refrigeration unit 24 or a conduit 25 bypassing the unit 24. The air flowing in the conduits 23 and 25 is merged and mixed in a manifold 26 whence it is released to the cabin cockpit through oneer more conduits 21.

The air flow in conduit 23 to the unit 2.4 passes through an intercooler 28 and thence through an air turbine 29 which in turn drives a fan 3U inducing a cooling air flow through the `intercooler 2-8. The turbine 29 extracts heat from the cabin air supply in addition to the cooling eifect of the intercooler, and operates at such a `high speed that consideration must be .given to am celeration induced stresses by limiting the impact of the air thereon during the accelerating period.

The foregoing description relates to the huid injection and cabin pressurization arrangements as associated with or applied tothe iet turbine used in the 11i-Jie airplane. The lfluid iniectiou system described is used to obtain maximum .or emergency power for a short time, and it has been found that the huid so injected into the turbine compressor' acts to also humidify the air withdrawn therefrom for the operation of the flight instruments Vand the pressurization oi the cockpit at high altitudes. The excess or exn (lessive humidity, even though supplied for only a short time interval, resulted in rusting and/or malfunctioning of the flight instruments, and fogging in and condensation on the cold Walls oi the cockpit and the cockpit Canopy.

y The apparatus of this invention `comprises gate Valves 3l ,Simultaneously opening or closing the connection between the taps I3 and the manifold i9, which valves are simultaneously operated by a piston .32 in a cylinder 33 as shown in Figure 2. The piston 32 is urged to the Valve open position by a spring 334 and moved to the valve closed position by pressure in the fluid injection circuit, which is tapped at the diaphragm controlled valve L by a cond-uit 35 leading to the cylinder 33.

The valve l5 is spring loaded so that the diaphragm will not open it until the pump i 3 builds up a Working pressureof about pounds in the fluid, thus delaying iiuid injection until sufcient pressure is available to assure proper injection at the nozzles i1. the initial fluid delivery to the cylinder 33, the spring 3s being so chosen that the piston 3F?. will be .moved to the right to close the air taps i8 before the start o f injection upon opening of the valve I5.

A one way restriction or check` Valve 36 in the conduit has a poppet 3l, is spring loaded to open for full flow from the valve i5 to the cylinder 33 and to close to restrict the return flow cr bleed by a small orifice 38 in the poppet 37 thus delaying the return movement of the piston 32 upon loss of pressure in the fluid injection circuit. This gives a time-delay period for the gradual restoration of the cabin pressure air supply after fluid injection into the turbine compressor has ceased. l

I f desired, a spring opened drain valve 35 may be connected to the conduit 35 to provide positive drainage of the latter in the event back flow through the idle pump l5 is insuiiicient to restore the cabin pressure air in the desired time interval. The valve 39 can be set to open at a pressure below that needed to operate the piston 32` so that it will be closed by iluid pressure in the conduit `35 but will open as the pressure This pressure build up diverts 4 below the check valve 3S is released, to permit the check valve 35 to control the bleeding or uid return from the cylinder 33.

It will thus be seen that I have provided means automatically to shut off the air bleeds for the instruments and cockpit pressurization upon or before star-ting fluid injection, andto restore the air supply kupon completion or shut-oli of the fluid injection. The restoration of the air supply to the cockpit is desir-ably delayed or restricted to the permissible rate of acceleration of the refrigeration turbine. The apparatus as hereinbefore described provides an improved and simplifled control for such purposes that is entirely automatic inaction, to preclude damage or neglect resulting from `pilot inattention or error.

Having thus described my invention and the vpresent preferred embodiments thereof, I desire to emphasize the fact that many modifications may be resorted to in a manner limited only by a just interpretation -of the following claims.

.Iclalm asmy invention; j t

1.. .In combination with a turbo-compressor wherein the compressor is bled to provide ,a source of compressed air, and said compressor has a fluid injection system to provide short bursts of increased power, a sequencing control for both the bled air and the fluid injection system, including at least one shut olf valve asso ciated with the compressor air bleed, means for operating said shut 01T valve comprising a valve operating mechanism arranged to close said shut off; valve in response to fluid pressure in said fluid injection system, a preloaded shut off valve in the uid vinjection System opening in response to a higher pressure than that required to operate said iirst mentioned shut 01T valve, a fluid connection from the fluid injection system to said mechanism, and a .check valve in said iiuid connection with a bleed opening therethrough so arranged as to delay the reopening movement of said valve operating mechanism upon release of pressure thereon.

2. In combination with a turbo-compressor wherein the compressor is bled to provide a source of compressed air, and said compressor has a fluid injection system to provide short bursts of increased power, a sequencing control for both the bled air and the fluid injection system, including at least one shut off valve associated with the compressor air bleed, means for operating said shut off valve comprising a valve operating mechanismv arranged to close said shut off valve in response to fluid pressure in said fluid injection system, a preloaded shut oi valve in the fluid injection system opening in response to a higher pressure than that required to operate said rst mentioned shut oft` valve, a iiuid connection from the fluid injection System to said mechanism, a check valve in said fluid connection witha bleed opening therethrough so arranged as to delaythe reopening movement of said valve operating mechanism upon release of pressure thereon, and means for bleeding said fluid connection upon release of pressure therein when the fluid injection system is not operating.

3. A sequencing control for inter-related primar-y and secondary working uid supply circuits where the primary iiuid circuit must be shut oli when the secondary uid circuit is operating, comprising a control valve in said primary fluid circuit, spring returned fluid operated means for said control valve having a fluid connection to said secondary fluid circuit, said means being arranged to close said control valve when subjected 5 to fluid pressure in said secondary fluid circuit. a UNITED STATES PATENTS preloaded pressure responsive valve normally Number Na e Date closing said secondary fluid circuit arranged t0 040,707 11051112111 an 9' 1900 build up pressure in said uid connection to close 757 692 Thompson APL 19 190,1z said control valve prior to delivery of fluid 5 929:852 H'osford Aug 3 1909 through Said Secondary llid Circuit, and a 1 525859 Fi'erra Feu 10 1925 bleeder type check valve in said fluid connection 1 591,071 Manders Ju1y 0 1920 arranged to slow down the release of fluid from 1:801'742 Hand June 7: 1932 Said Spring' returned fluid Operated means upon 1,905'065 Shan Apr. 25, 1933 de-BIIBI'gZaOn 0f the SeCOndafly fluid Circuit 10 1,980,478 Frentzel N0v 13' 1934 2,038,998 Hammond Apr. 28,1936 EDWARD R- DERRINGTON 2,559,814 Whittle Ju1y 1o. 1951 REFERENCES CITED FOREIGN PATENTS The following references are of record in the 15 Number Country Date file of this patent: 471,540 Great Britain 1937 67.997 Sweden 1927 

